Monarch Conservation

North American monarchs are in trouble.

The monarch is one of the best-known and most beloved butterflies in North America, occurring throughout a broad range of habitats across the U.S. and into southern Canada and central Mexico. Two populations migrate to overwintering sites each fall: monarchs east of the Rocky Mountains migrate primarily to high-elevation forests in central Mexico, while most monarchs west of the Rockies migrate to hundreds of smaller, wooded groves along the California coast. Yet, this once-common butterfly now faces an uncertain future, with annual monitoring of overwintering monarchs in central Mexico and along the California coast revealing significant population declines. In the 1990s, estimates of up to one billion monarchs made the epic flight each fall to Mexico, and more than one million monarchs overwintered in forested groves along the California coast. Now, researchers and citizen scientists estimate that only a fraction of the population remains. At the central Mexico overwintering sites, scientists have documented a decline of more than 80%, while in coastal California researchers have documented a decline of over 95% since the 1980s.

In the eastern U.S., researchers have identified loss of milkweed as one of the most significant factor contributing to the observed declines of monarchs; it is thought that loss and degradation of monarch breeding sites in the West has triggered similar declines. Other threats include climate change, pesticides such as neonicotinoids, loss and degradation of overwintering sites, parasites and disease. To better understand what threats monarchs and milkweeds face and where habitat has been lost, we must understand where are they exist in the western landscape. Enter the Western Monarch Milkweed Mapper! Data from the Mapper has informed a Habitat Suitability Model, which along with a recent isotopic study suggesting that the natal origin of overwintering monarchs in California come from across the West, have highlighted large key breeding areas; however, more data is needed in order to improve conservation and restoration work on the ground.

Conservation at Work

The Xerces Society and our partners are working to protect and manage the habitats that support all life stages of the monarch’s life cycle. We work at local, state, national, and international levels to promote monarch conservation efforts. In the West, this includes holding workshops for land managers, training biologists and volunteers to conduct surveys for milkweed breeding habitat, developing citizen science programs and tools to better address conservation issues specific to western monarchs, and restoring habitat with farmers, ranchers, and other land managers. See our monarch conservation update for a summary of efforts and ongoing partnerships and learn more on our Monarch page.

How Can I Help?

Are you interested in supporting monarch conservation? There are a number of ways you can contribute, too!

Take photos of monarchs and milkweeds in your area and submit your sightings to the Western Monarch Milkweed Mapper.

In areas where milkweed and nectar plants have been lost, consider creating or restoring habitat. Monarchs need nectar-rich flowers as adults and milkweeds for their young. Find monarch nectar plant lists and milkweed seeds for your region.

About the Western Monarch Milkweed Mapper:

The Western Monarch Milkweed Mapper is a project through the partnership of The Xerces Society, Idaho Department of Fish and Game, Washington Department of Fish and Wildlife, National Fish and Wildlife Foundation, and US Fish and Wildlife Service. Learn more about this project.